Joe Jackson arrived to the L.A. County Courthouse today for the Michael Jackson probate case with a bit of an attitude. When asked about entertainment lawyer and co-executer in Michael’s will, John Branca, Joe said, “Mr. Who?” TMZ reports.

TMZ says that some family members, as well as attorney Brian Oxman and possibly Katharine Jackson’s lawyers, are expected to challenge Branca as the named co-executor in Jackson’s will. They supposedly have a document showing Michael fired John. That’s true, but Michael fired and rehired him many times over a span of 29 years. Michael had rehired Branca a week before his death.

At 1:30 PM PT the judge will hear both sides of how Michael’s children are doing under the guardianship.